Marine Planning

Marine Planning

Marine planning contributes to the sustainable use of our coasts and seas through managing and balancing the activities occurring in our coastal and offshore waters. It aims to make the most of our marine space, whilst ensuring a sustainable future for our marine environment.

Marine planning follows a similar approach to terrestrial planning – setting the direction for decision making at a local level. Marine plans are used by public authorities as part of the decision-making process for all new activities and developments affecting the marine area.

As the Severn Estuary is a cross-border site, activities should consider both the Welsh Government and the Marine Management Organisation (MMO) and their marine plans. Take a look at the animation below for more Marine Planning in the Severn Estuary, specifically in reference to the South West Marine Plan in England and what this means for a cross-border area.

Marine planning will:

  • Guide marine users to the most suitable locations for different activities.
  • Manage the use of marine resources to ensure sustainable levels.
  • Work with all marine users to ensure everyone has an opportunity to contribute to marine plans.
  • Take a holistic approach to decision making and consider all the benefits and impacts of current and future activities that occur in our marine environment.

Marine Planning EnglandMarine Planning Wales
The Marine Management Organisation (MMO) was established following the Marine and Coastal Access Act 2009 and has responsibility for preparing marine plans for English inshore and offshore waters. The offshore marine plan area is the area from 12 nautical miles offshore to the Exclusive Economic Zone. Wales, France, Ireland, Guernsey and South Marine Plan areas border the plan area. The MMO has a duty to take decisions on proposed developments in the plan area in accordance with the Marine Policy Statement 2011 (MPS) and marine plans unless relevant considerations indicate otherwise.

The MMO has responsibility to:

• Design a planning process suitable to deliver marine plans.
• Work with the public to integrate and balance all current marine and future activities into a comprehensive plan.
• Deliver a marine plan for each marine plan area, monitor and review plans on a regular basis.

The Marine Management Organisation is preparing plans for 11 areas in England. The first set of marine plans for English waters providing more detailed, area-specific guidance on marine issues. The first plans, the East Marine Plans, were published in 2014. The South Marine Plans were the second to be adopted in 2018. These have been followed by plans for the North West, North East, South East and South West, with all plans on course to be in place by 2021.
The MMO have been developing the marine plan for the South West marine plan area.  The South West marine area includes 2 plan areas, the South West inshore and the South West offshore marine plan areas. The South West inshore marine plan area covers an area of approximately 2,000 kilometres of coastline stretching from the River Severn border with Wales to the River Dart in Devon, taking in a total of over 16,000 square kilometres of sea. You can view all the Marine Plan Areas in England here.

For more information on the South West Marine Plan, watch our Marine Planning animation above. This animation was produced as part of the ‘Enhancing Stakeholder Engagement’ project with the Marine Management Organisation and funded by the European Maritime and Fisheries Fund (EMFF).

For more information on marine planning contact the MMO team at or to sign up for the MMO Marine Planning e-newsletter click here.
Welsh Government published the first Welsh National Marine Plan (WNMP) in November 2019. It sets out Welsh Government’s policy for the next 20 years for the sustainable use of Wales’ seas. In contrast to the English marine plans, the Welsh National Marine Plan is not currently split into regional areas, and therefore, Welsh Ministers are the planning authority for the Welsh:

• Inshore region (out to 12 nautical miles)
• Offshore region (12 to 200 nautical miles)

The WNMP contains plans and policies for both the inshore and offshore regions. It aims to:
• Support the vision for clean, healthy, safe and diverse seas.
• Guide future sustainable development.
• Support the growth of marine space and natural resources or blue growth.

Implementation guidance has also been published to help authorities understand the decisions they will need to take. There are a series of useful resources on the Welsh Government website about the Marine Plan, including webinars, an animation and infographics.


The Severn Estuary is one of the largest estuaries in Britain and has the second highest tidal range in the world.

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